[postmodern-devel] Join Slots

I'm considering to change from clsql to postmodern because I need unicode support. In clsql the following viewclass definition is possible with join slots: (clsql:def-view-class elements () ((guid :reader element-guid :db-kind :key :type (string 36)) (lang_id :db-kind :key :type (string 2)) ... more ... 'normal' slots) (produkt :reader product-element :db-kind :join :db-info (:join-class produkte :home-key (guid_objekt lang_id) :foreign-key (guid lang_id) :set nil))) (:base-table project-elements)) so that I can access the joined records easily via (product-element instance-of-element) How do I do this with postmodern? Thanks Jens